The Vikings and the authority overseeing the stadium told Audubon last year they would turn off stadium lights at night to lower risk to birds. But Audubon says that's only a partial solution. They say using a safer glass would amount to a tiny fraction of a billion-dollar stadium that's getting hundreds of millions of public dollars.

An MSFA spokeswoman said the agency had no immediate comment. A Vikings spokesman didn't immediately return a call.

This time last year the Apostle Islands Ice Cave season was about to wrap up, but this year, it's just getting started, and the shorter season had crowds flocking to the attraction for its opening weekend. Just days ago, park officials gave the okay for the ice caves to open up to the nearly 11,000 visitors who came over the weekend.